I’ve been watching flights on FlightAware with interest since January this year but unable to get a valid answer what’s going on with GA traffic in NZ. Has anyone else picked it up?
For the record I install ads-b (out) in gliders but what I’m seeing on FA has me foxed.
Presumably the influx of new transponders since the dec 31 deadline the database is a bit behind.
What do you mean by an “unknown target”?
ICAO (unassigned?) B prefix ads-b ‘out’ identification code eg B1200EH showing as the identification with a small jet icon.
I can see the TSV lines of data for the flights and the schedule of flights done but the tracks don’t start and finish like normal aircraft.
They often start and finish a track near an airport but not in line with runways and also will start or finish in odd places - similar to a pilot switching the ADS-B on or off in flight at will.
No data for altitude is visible and the TSV data lines are a minute or can be many minutes apart compared to about 15 second apart for other aircraft.
I have only been able to find these in New Zealand.
Have a look for yourself. I am being told they are some kind of computer artifact although would expect Airways NZ to have an IT person that would have sorted it out by now.
The sheer numbers of these things piqued my interest enough to do a bit of research on modern uas/uav technology to find out if the flight parameters I’m seeing are possible. GPS speeds range from 0 through to 270 kts and endurance up to 4.5 hours.
They don’t follow commercial flights but will tail GA light aircraft 24/7.
I fly light aircraft and gliders, and also install ADS-B in gliders so want to know what these are, or why they show only on FlightAware.
I wondered if this was leading down the road to the B thing.
They’re non commercial routes/aircraft. This one was the Otago rescue chopper heading north.
Presumably the system doesn’t get a great supply of flight details for smallfry.
For B1200EH, the data is exclusively from Airways NZ. The lack of altitude is a peculiarity of the data feed we get from AWNZ. It’s perhaps radar data in this case – I don’t see any ADS-B in the same area at the same time (though maybe it was just below our coverage in the area, given terrain)
For B15001E, that data is again from Airways NZ. I found a matching ADS-B track, but that aircraft is blocked so I don’t have a public flight track to share with you. There wasn’t anything in the Airways NZ data that would let us pair it up with the ADS-B data (in particular, the ADS-B ident wasn’t B15001E, so I’m not sure where it’s coming from)
Oddly displaying 0 alt too.
I’ll get a daytime example at some point to see if there isn’t some massaging needed.
I can see from NZCH history multiple Training flights doing ch to ch with similar idents. And they definately have adsb (it was mandated for all controlled airspace from dec31)
If it was only radar data from Airways NZ wouldn’t it only be a track rather than TSV lines of data or could this be a function of MLAT? Why the longer periods between data blocks?
I spent an hour copying down all the different Bxxxxx targets showing on the screen the other day and totaled about 50 during that period. Rather a lot for an anomaly, and most with a history of viewable flights throughout NZ in the schedule.
I watched on Flightaware a mates flight for about an hour a couple of weeks back. Also tagging along was one of these B targets. The interesting thing is that when my mate did some holding turns while waiting for parachutists to land at a nearby airfield, the B target did a bit of a weird reversal along it’s track rather than turns. It is actually quite entertaining watching them.
What I don’t understand is that our club aircraft with the former mode C transponders don’t show up on Flightaware or Flight Radar 24 for that matter, yet you mention Airways could be picking up these B targets on radar? In my understanding, you only get TSV/CSV data lines from a GPS derived source, although I understand that with enough private repeaters set up around the place it is getting possible to triangulate data from mode A and C transponders to give lat and longt data without GPS. Isn’t this what MLAT is about?
Where did you see it was the Otago rescue helicopter?
There’s more than one tracker and I have a receiver too 
I’ve watched quite a few rescue helicopters and they all showed legit identification - usually not NZ rego, and most had one of these B targets nearby.
Interesting.
Both McKenzie helis - IKL is a 369D with code C81B4B and HBX is a Squirrel C81206.
Were both giving a B ID or just one?
I have watched a military aircraft with a B code on a couple of occasions now and can see police when their ads-b is off, but they do not have a B ID… 
Both Bs on those targets
What day and time were these please? I was just looking at the flights for IKL and there are plenty!
Today at 1253. It’s live flight data. Not historical. Open the map. Click on some targets. Compare to 3 other tracker sites.
Look over north Canterbury now. There is some form of pinged radar B… And nearby it a more accurate adsb
I’m not sure which TSV you’re referring to.
FlightAware fuses data from many sources (Airways NZ and other ANSPs, our own ADS-B and Mode S MLAT network, datalink, etc) into a single flight track, and then that fused data is what our website and APIs provide. You can see the data source for a position as the “reporting facility” in tracklogs.
In this particular case it was Airways NZ data only. No FlightAware-derived MLAT or ADS-B. The interval is the interval we got from AWNZ. We don’t have further visibility into how AWNZ derived the position - it could be from ADS-B, secondary radar, multilateration, …
I am trying an app called unfiltered ads-b and this seems to bring up a lot more helicopters.
Will play around with multiple trackers for a bit.
Kinda weird why this is only a problem in NZ with Flightaware.
Just to answer your query. The TSVs (tab separated values), or track log lines I refer to is any or all related to these B idents. Always no alt and at least a minute apart.
Is there a problem with Airways NZ data somehow?
I passed this on to the team which looks after the Airways feed to see if we can get any upstream improvement in data quality there.